I'll try to explain better my situation and what I'm trying to achive.

So my main goal: There is a shared folder with documents in local network, users that will be using this app should not have access to this shared folder, only entity that is running App pool has access to it.

I am making some SQL request that gives me path of some subfolder. I am building treeview of that subfolder and when user clicks on some file in treeview SelectedNodeChanged event shots and I perform transmitting file as app pool identity

Everything is working fine but if I understand right, something on CLIENT side probably freezes page after TransmitFile shoots and prevents from sending any other post request to server, that's why my little JS solution worked when it was performed OnClientClick.

Nodes doesn't have onClientClick event, but we can add JS click event to any page element, right? So here is the trick, when creating TreeView just add click to actual text of the node with help of Span: